The grasslands of the San Juan Islands were once maintained by wildland fires (both naturally occurring, and set by and set by Coast Salish peoples). Camas (Camassia spp.) was an important food source, and figured prominently in cultural practices of the native inhabitants. Settlement by European and American migrants brought livestock grazing and cultivation, reduced the frequency of fire, and resulted in the introduction of numerous non-native plants which have invaded the landscape.

Most of the grasslands in the San Juans, including those on BLM lands, are largely composed of non-native grasses, and support a mixture of native and non-native forbs. Grasslands are also being invaded by woody shrubs such as blackberry (Rubus spp.) and Scotch broom (Cytisus scoparius).